diagnostic accuracy of computed tomography in neoplastic invasion of the laryngeal cartilage

Cartilage invasion is important in the management plan of laryngeal and hypopharyngeal neoplasms. This study was conducted to determine the diagnostic accuracy of computed tomography [CT] to detect the neoplastic invasion of the laryngeal cartilages. 37 patients with proved laryngeal or hypopharyngeal neoplasm that were candidates for total laryngectomy were included in this study. For all patients, standard contrast-enhanced laryngeal CT was performed. Two imaging findings were considered as neoplastic invasion of the laryngeal cartilage increased density and chondrolysis. These findings were evaluated in thyroid, cricoid and arytenoid cartilages. Then, all patients underwent total laryngectomy and the cartilages were sent for histopathologic evaluation. The sensitivity, specificity, positive predictive value, negative predictive value and positive and negative likelihood ratios of CT findings were evaluated for the diagnosis of neoplastic invasion of these cartilages. The mean [ +/- SD] age of patients was 61.4 +/- 8.8 [range: 39-76] years. Thirty-four patients were male; 25 had laryngeal tumor and 12 had hypopharyngeal tumor. Totally, 139 cartilages were evaluated [37 thyroid, 37 cricoid and 65 arytenoid cartilages]. Among these cartilages, 49 [16 thyroid, 11 cricoid and 22 arytenoid cartilages] had neoplastic invasion. In thyroid cartilage, the sensitivity of increased density was 0.81 and the specificity of chondrolysis was 0.91; the specificity of both findings together was 0.95. In cricoid cartilage, the sensitivity of increased density was 0.73; the specificity was 0.73; the specificity of chondrolysis was 0.96 and specificity of both findings was 1. In arytenoid cartilage, the specificity of increased density was 0.67; the specificity of chondrolysis was 0.98; and the specificity of both findings together was 1. Considering all 139 cartilages together, the sensitivity of increased density was 0.69 and the specificity of chondrolysis was 0.96. Setting all cartilages in a single group and considering both of these CT findings, the sensitivity was 0.89 and the specificity was 0.76. Chondrolysis is a specific and increased density is a relatively sensitive CT finding for the diagnosis of laryngeal cartilage neoplastic invasion; considering both findings together makes a very specific imaging finding for the diagnosis